{"id":32300,"date":"2025-06-22T12:35:09","date_gmt":"2025-06-22T12:35:09","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=32300"},"modified":"2025-06-22T12:35:11","modified_gmt":"2025-06-22T12:35:11","slug":"mercury-ii-carbonate-hgco3-is-a-salt-of-low-solubility","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/mercury-ii-carbonate-hgco3-is-a-salt-of-low-solubility\/","title":{"rendered":"Mercury (II) carbonate, HgCO3, is a salt of low solubility"},"content":{"rendered":"\n

Mercury (II) carbonate, HgCO3, is a salt of low solubility. When placed in water, it dissolves until an equilibrium is reached. The mercury (II) ion, Hg2+, is diatomic. The balanced equation for the dissolution of Mercury (II) carbonate is: HgCO3(s) \u00e2\u2021\u0152 Hg2+(aq) + CO3^2-(aq). Write an expression for the solubility product constant, Ksp, of Mercury (II) carbonate.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

1. Solubility Product Expression (Ksp) for Mercury(I) Carbonate<\/strong><\/h3>\n\n\n\n

The dissociation of mercury(I) carbonate is given by:<\/p>\n\n\n\n

Hg\u2082CO\u2083 (s) \u21cc Hg\u2082\u00b2\u207a (aq) + CO\u2083\u00b2\u207b (aq)<\/strong><\/p>\n\n\n\n

Since this is a slightly soluble salt, its solubility product constant (Ksp) is expressed in terms of the concentrations of the dissolved ions at equilibrium. For the above equilibrium, the Ksp expression is:<\/p>\n\n\n\n

Ksp = [Hg\u2082\u00b2\u207a][CO\u2083\u00b2\u207b]<\/strong><\/p>\n\n\n\n

Here:<\/p>\n\n\n\n

    \n
  • [Hg\u2082\u00b2\u207a] is the molar concentration of the diatomic mercury(I) ion in solution<\/li>\n\n\n\n
  • [CO\u2083\u00b2\u207b] is the molar concentration of carbonate ion in solution<\/li>\n<\/ul>\n\n\n\n

    Because Hg\u2082CO\u2083 is a solid, its concentration is not included in the expression.<\/p>\n\n\n\n

    \n\n\n\n

    2. Calculating the Solubility of Mercury(I) Carbonate<\/strong><\/h3>\n\n\n\n

    Given:
    Ksp = 8.9 \u00d7 10\u207b\u00b9\u2077<\/strong><\/p>\n\n\n\n

    Let the solubility of Hg\u2082CO\u2083 be s<\/strong> mol\/L. When one mole of Hg\u2082CO\u2083 dissolves, it produces:<\/p>\n\n\n\n

      \n
    • 1 mole of Hg\u2082\u00b2\u207a<\/li>\n\n\n\n
    • 1 mole of CO\u2083\u00b2\u207b<\/li>\n<\/ul>\n\n\n\n

      So, at equilibrium:<\/p>\n\n\n\n

        \n
      • [Hg\u2082\u00b2\u207a] = s<\/li>\n\n\n\n
      • [CO\u2083\u00b2\u207b] = s<\/li>\n<\/ul>\n\n\n\n

        Substituting into the Ksp expression:<\/p>\n\n\n\n

        Ksp = [Hg\u2082\u00b2\u207a][CO\u2083\u00b2\u207b] = s \u00d7 s = s\u00b2<\/strong><\/p>\n\n\n\n

        Therefore:<\/p>\n\n\n\n

        s\u00b2 = 8.9 \u00d7 10\u207b\u00b9\u2077<\/strong>
        s = \u221a(8.9 \u00d7 10\u207b\u00b9\u2077)<\/strong>
        s \u2248 9.43 \u00d7 10\u207b\u2079 mol\/L<\/strong><\/p>\n\n\n\n

        \n\n\n\n

        Explanation<\/h3>\n\n\n\n

        Solubility product constant (Ksp) is an equilibrium constant used for sparingly soluble salts. It reflects the extent to which a compound dissociates into its ions in water. In this problem, mercury(I) carbonate is only slightly soluble. Its dissociation in water produces two types of ions \u2014 the diatomic mercury(I) ion (Hg\u2082\u00b2\u207a) and the carbonate ion (CO\u2083\u00b2\u207b).<\/p>\n\n\n\n

        The balanced chemical equation shows a 1 to 1 molar ratio for the ions produced. This simplifies the Ksp expression since both ion concentrations are equal at equilibrium. By defining the solubility (s) as the number of moles of Hg\u2082CO\u2083 that dissolve per liter of solution, we determine that the concentrations of Hg\u2082\u00b2\u207a and CO\u2083\u00b2\u207b are both equal to s.<\/p>\n\n\n\n

        Since both ions appear in a 1:1 ratio, the Ksp expression becomes the square of the solubility:
        Ksp = s\u00b2. Solving this equation gives the numerical solubility value.<\/p>\n\n\n\n

        The very low Ksp value (8.9 \u00d7 10\u207b\u00b9\u2077) confirms that mercury(I) carbonate is highly insoluble in water. The final solubility, 9.43 \u00d7 10\u207b\u2079 mol\/L, is also very small, reinforcing the point that only a tiny amount of the salt dissolves before equilibrium is reached.<\/p>\n\n\n\n

        This method of using the square root of Ksp applies whenever the dissolution produces a 1:1 molar ratio of ions. For salts that produce ions in different ratios (like 1:2 or 2:3), the setup and algebra for solving solubility would require different exponents and adjustments.<\/p>\n\n\n\n

        \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

        Mercury (II) carbonate, HgCO3, is a salt of low solubility. When placed in water, it dissolves until an equilibrium is reached. The mercury (II) ion, Hg2+, is diatomic. The balanced equation for the dissolution of Mercury (II) carbonate is: HgCO3(s) \u00e2\u2021\u0152 Hg2+(aq) + CO3^2-(aq). Write an expression for the solubility product constant, Ksp, of Mercury […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-32300","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/32300","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=32300"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/32300\/revisions"}],"predecessor-version":[{"id":32307,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/32300\/revisions\/32307"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=32300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=32300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=32300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}